Memory subsystem performance
We'll begin with a look at memory performance, so we can get a feel for some fundamentals of these CPUs.

The X4 955's L1 and L2 caches are proportionately faster than those of prior Phenom IIs at each test block size.

Since it's difficult to see the results once we get into main memory, let's take a closer look at the 256MB block:

With DDR3 memory, the Phenom II X4 955 achieves the exact same throughput as its smaller-cache sibling, the X4 810. That's nearly as much bandwidth as the Core i7-920, which has the benefit of an additional channel of DDR3 memory (albeit at a lower clock speed of 1066MHz).

The X4 955's memory latency is admirably low, as well. No real surprises here, but you can see that, thanks to its integrated memory controller, fast cache hierarchy, and DDR3 memory, the Phenom II X4 955 scores among the best CPUs available in our synthetic memory subsystem benchmarks.